Forgers foiled

Lumenia, a joint venture company set up by Xennia and the University of Leeds, has created ink that changes colour when photocopied or scanned, to prevent forgers colour matching banknotes.

‘Photocopying brings about a colour change in certain printed areas. This change, say from red to green, is reversible within minutes because the ink on the original document or banknote returns to its original colour but the scanned or photocopied sample will always be green,’ said Professor DM Lewis, head of the Department of Colour Chemistry at Leeds University.

‘The molecule which achieves this effect is truly thermochromic and was invented by my colleagues in Lumenia, Dr Long Lin and his wife Dr Wei Dong He.’

The team has also created a ‘magic pen’ which can wipe out ink on forged bank notes and an ink that, when used in an ordinary inkjet printer, stays visible for a set period of time before fading off the page.